The invention relates to a straight-through dishwasher in the case of which the carrier bodies accommodating the dishes which are to be cleaned are conveyed through the straight-through dishwasher by means of a transporting mechanism which comprises a transporting carriage. A carrier rack is usually provided for straight-through dishwashers, and this makes it possible for the dishes to be easily transported even outside the machine on conveying belts or curves. The items for washing can be easily introduced into the carrier racks and also easily removed again therefrom. During slack periods, with only a small amount of dishes, the dishes which are to be cleaned are first of all collected in a plurality of carrier racks, with the result that the machine can be operated cost-effectively, i.e. only with fully loaded carrier racks.
Longitudinally extending lateral rack-guide rails which are fitted in the machine interior ensure that the carrier racks are transported through the straight-through dishwashers. The carrier rack rests on said rack-guide rails. Located beneath the rack-guide rails is a transporting element which is of carriage-like design and is provided with tilting catches which allow a pivoting movement. The tilting catches automatically rotate into a certain position on account of their configuration and mounting, with the result that the tips of the tilting catches project into a ribbing arrangement which is formed on the underside of a carrier body. The tilting catches may be configured, for example, in the manner of a barb and, during a forward movement of the carriage-like transporting element, push the carrier rack forward in accordance with the length of a stroke movement. In the case of a rearward movement of the carriage-like element being executed, the rotatably mounted tilting catches can move away downward beneath the ribbing arrangement of the carrier rack until they can move into the upright position again in a rib interspace on the underside of the carrier rack. This means that the carrier basket remains stationary during the rearward movement of the carriage-like transporting element. In the case of a renewed forward movement of the carriage-like transporting element, the tilting catches engage in the ribbing arrangement of the carrier rack again and push the carrier rack forward in accordance with the stroke movement of the carriage-like transporting element.
Common configurations of the carriage-like transporting element are provided by a single stroke-executing carriage which is arranged centrally between the rack-guide rails and of which the tilting catches engage in the center of the carrier rack. Another variant provides a rigid rectangular frame, of which the two carriage profiles provided with the tilting catches engage on the outer borders of the carrier rack. The carriage profiles extend laterally, in the longitudinal direction of the machine, in the region of the rack-guide rails.
The forward and rearward movement of the carriage-like transporting element is produced in that the rotary movement of a gear motor is converted, by means of a crank mechanism, into a purely forward and rearward movement of the guide-like transporting element. Depending on the configuration of the crank mechanism, it is possible to realize stroke movements which are between approximately 80 mm and 250 mm per motor revolution. On account of this design principle, the carrier rack with the items for washing located therein, rather than being conveyed through the machine at a uniform transporting speed, is only transported during a half motor revolution and remains stationary during the other half motor revolution, when the carriage-like transporting element executes a rearwardly directed movement. This technology does indeed realize a straightforward design principle, which allows cost-effective production and constitutes a robust possible configuration.
The disadvantage with this design principle, however, is the fact that the transporting movement of the carrier rack, rather than running uniformly, is interrupted. It is thus the case that, with the same average transporting speeds and otherwise identical washing parameters as for a continuous belt machine, a poorer washing result is achieved in comparison with the latter. Average transporting speed is to be understood as the overall distance which the carrier rack has to cover divided by the time required for this purpose.
In order to compensate for the standstill time of the carrier rack, which takes place during the rearward stroke of the carriage-like transporting element, the carrier rack is moved at far more than double the transporting speed during the forward movement. The design results in the ratio of advancement time to standstill time of the carrier rack being approximately 40 to 60. This means that the carrier rack is only moved during 40% of the time which the output shaft of the gear mechanism requires for one revolution, and which is theoretically available for the advancement, and is stationary during 60% of this time.
The washing result depends directly, inter alia, on how long a flat spray jet from individual nozzles works on the soiled surface of the items for washing. A non-uniform movement sequence with its brief phases of high transporting speed has an adverse effect on the washing result achieved. The strokewise movement of the carrier rack with its brief phases of high transporting speed has a particularly disadvantageous effect, in this context, on the result of the rinsing with clean water. In the clean-water rinsing zone, a fan-like spray jet is only produced over a single line, transversely to the direction of travel of the carrier rack, said spray jet coming into contact with the surface of the items for washing. The rinsing result, via the spray jet, on a glass which passes said linear spray jet, on account of the jerky movement having a brief high-speed phase, is not satisfactory.
EP 0 917 277 A1 relates to a motor drive. The motor drive comprises devices for translating the rotary movement of the drive shaft into a reciprocating linear movement. The motor drive preferably serves for driving a reciprocating transporting rail of a straight-through dishwasher. A bearing comprising two half-shells of semicylindrical cross section is provided on a drive shaft. At least one of the half-shells interacts with a switching device. When a certain lateral deflection of the at least one part-shell is exceeded, the switching device switches the motor drive in particular.